GaAs photovoltaics are promising candidates for indoor energy harvesting to power small-scale (≈1 mm2) electronics. This application has stringent requirements on dark current, recombination, and shunt leakage paths due to low-light conditions and small device dimensions. The power conversion efficiency and the limiting mechanisms in GaAs photovoltaic cells under indoor lighting conditions are studied experimentally. Voltage is limited by generation–recombination dark current attributed to perimeter sidewall surface recombination based on the measurements of variable cell area. Bulk and perimeter recombination coefficients of 1.464 pA/mm2 and 0.2816 pA/mm, respectively, were extracted from dark current measurements. Resulting power conversion efficiency is strongly dependent on cell area, where current GaAs of 1-mm2 indoor photovoltaic cells demonstrates power conversion efficiency of approximately 19% at 580 lx of white LED illumination. Reductions in both bulk and perimeter sidewall recombination are required to increase maximum efficiency (while maintaining small cell area near 1 mm2) to approach the theoretical power conversion efficiency of 40% for GaAs cells under typical indoor lighting conditions.
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机译：GaAs光伏技术有望成为室内能量收集的候选人，以为小规模（≈1mm 2 ）电子设备供电。由于低光照条件和小尺寸器件，该应用对暗电流，复合和并联泄漏路径有严格的要求。实验研究了GaAs光伏电池在室内光照条件下的功率转换效率和限制机理。电压受到生成-重组暗电流的限制，该暗电流归因于基于可变单元面积的测量的周边侧壁表面重组。从暗电流测量中得出的体积和周界复合系数分别为1.464 pA / mm 2 和0.2816 pA / mm。产生的功率转换效率在很大程度上取决于电池面积，其中1-mm 2 室内光伏电池的当前GaAs在580 lx白色LED照明下显示出约19％的功率转换效率。需要减少体积和周边侧壁的重组，以提高最大效率（同时在1mm 2 内保持较小的电池面积），以便在典型的室内照明条件下使GaAs电池的理论功率转换效率达到40％ 。
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